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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Verdana","sans-serif";color:#1F497D">OK i’ve fixed these. will push when I have valiated<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Iavor Diatchki [mailto:iavor.diatchki@gmail.com]
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<b>Sent:</b> 14 January 2013 18:40<br>
<b>To:</b> Simon Peyton-Jones<br>
<b>Cc:</b> ghc-devs@haskell.org<br>
<b>Subject:</b> Re: Failing test<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hello,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
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<p class="MsoNormal">On Mon, Jan 14, 2013 at 9:52 AM, Simon Peyton-Jones <<a href="mailto:simonpj@microsoft.com" target="_blank">simonpj@microsoft.com</a>> wrote:<span style="font-family:"Verdana","sans-serif""> </span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif"">Are these four failures the result of your changes?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif"">Should we fix the tests?</span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">(sorry, this went to the fun-dep thread so it probably got buried among the other e-mails).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">About the tests: <span style="font-size:10.0pt;font-family:"Arial","sans-serif"">When I ran the type-checker tests, I got these 3 failures that I am not sure how to fix:</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Unexpected failures:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> should_compile tc226 [exit code non-0] (hpc,optasm)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> should_compile tc235 [exit code non-0] (normal,hpc,optasm)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> should_fail T5684 [stderr mismatch] (normal)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">- tc226 appears to be completely unrelated to my changes, so I imagine it is about something else?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">- tc235 is a program that is now rejected. I am not sure how to fix this test as the program inside seems incorrect at many levels (e.g., it violates the FD of the class,
but it also uses ambiguous methods). I also couldn't figure out what it is testing.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">- T5684 is still rejected but with a different error, because one of the instances violates the FD of the class. However, this test appears to be carefully designed to test
something else, but I didn't quite follow exactly what, so I left it as is for the moment.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Would you mind taking a look and advising on what to do? I think that the new behavior is correct for tc235 and T5684, but it would be nice to preserve whatever was originally
tasted there (unless it was an artifact of the lax checking of the FDs)<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif"">Should the error message say “The instance decl is inconsistent with the fundeps”? And maybe be more precise about which fundep.</span><o:p></o:p></p>
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<p class="MsoNormal">We could do that. The current message replaces "the Coverage Condition fails for one of the functional dependencies", because I thought that it is more descriptive. The way the tests is written---both the coverage condition, and the
new one---they return just a boolean, but I could probably to return the FD that is being violated. I'll have a go at it.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"> <span style="font-family:"Verdana","sans-serif""> </span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif"">I’m a bit confused.</span><o:p></o:p></p>
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<p class="MsoNormal">About which part? Here is an example of what we are checking for:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">class C a b | a -> b<o:p></o:p></p>
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<p class="MsoNormal">instance C Int b -- bad instance<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The instance violated the FD on the class because it implies that both `C Int Int` and `C Int Char` hold, which violated the FD. This is what I meant by "multiple uses of the instance may violate the functional dependency". The reason
I opted to go for "may" in the message is because strictly speaking the test is incomplete (i.e., there are somewhat contrived examples that are consistent with the FD, but would be rejected, I can send one if it'd be useful?).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-Iavor<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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